My Knife Sharpening Machines are now Solar Powered!

Today at Lunardi's San Bruno was the first day I used solar panels to operate the knife sharpening machines!

Solar Panels Powering my Knife Sharpeners

The above picture shows the panels. It took a bit longer to get this going than I thought. I am a mobile knife sharpener, so I wanted folding panels so that I can use, put away and also be able to store.

Behind the panels just visible is the inverter, the deep cycle battery is underneath the inverter. Now that I have all the components, the next step is designing the case for the battery and inverter. The battery is heavy, so I am looking at a rolling tool box type setup.

The knife sharpening equipment uses regular household AC power, the solar panels and the battery are DC power so the inverter is needed to convert the one to the other.

I had the battery and inverter already, I charged the battery at home, it ran the knife sharpener all day, then back home to recharge, rinse and repeat. I wanted the panels so that I would not have to lug the battery in and out — and also to keep the battery charged during the day. Some days I get quite busy, people lined up bringing me knives to sharpen so I was always worried that the battery would run down. Range anxiety as it were.

It took more time than expected as I ordered the solar panels, and twice there was a hitch — once the panels were returned to the seller, the second time I simply never received them. 

It was a very sunny day, and a busy day at Lunardi's — nobody brought me garden tools to sharpen today (which usually cause the knife sharpener to run longer), but plenty of kitchen knives and pocket knives. The panels did great, I started with a full battery and finished the day with a full battery!

With a few more days under my belt I will know how balanced the system is. The next test is this Saturday, I am sharpening at Kirkwood Plaza in Campbell. The weather forecast is a sunny day on Saturday, with my luck we will have either rain or fog or a heavy marine layer.  Come visit and check it out!

Solar Powered Mobile Knife Sharpening

This picture is the knife sharpening booth set up at Kirkwood Plaza. Right in front is the new solar panels. Kirkwood is day two of running on solar panels charging the agm battery. Just measuring battery voltage I think I ran down the battery a bit. 

I am not sure how accurate just measuring battery voltage is in determining state of charge — I find mention of letting the battery rest, or putting a load on it before measuring the voltage. In any case, the battery voltage seems to bounce around a bit. 

I hope the panels can keep pace...